The present invention refers to an electrical connector element with rewirable contacts, wherein the feed cable conductors can be inserted removably into the terminals of the connector element.
In the field of connectors for industrial environments various market standards have become consolidated over time in terms of size, number of poles and rated voltages. Amongst these there are connectors measuring 21 mm×21 mm, with 3 or 4 poles plus an earth contact, for currents of 10 A and a rated voltage of 250V. These connectors are provided with plastic or metal cases, are produced by numerous manufacturers and are generally mechanically and electrically interconnectable with each other.
A research is currently under way among manufacturers to put onto the market connectors that are able to work with increasingly high rated voltages, though maintaining the same dimensions as the connectors of the standard type used until now and being interconnectable therewith.
The connector elements of the prior art with rewirable contacts, because of the above mentioned industry standard, have insulation piercing terminals or screw terminals.
The connector elements with screw terminals have a body of insulating plastic material. A first seat is formed in the body to house the part of the terminal that must accommodate the conductor of the feed cable and a second seat to house the screw to be screwed into the terminal to clamp the conductor therein.
The conductors can be inserted axially from the top of the body, and the clamping screws can work transversally from one side of the body of the connector element. In this case the heads of the screws remain very close to the walls of the metal case, which surrounds the body of the connector element.
Alternatively, the conductors can be inserted transversally from one side of the body of the connector element and bent upwards at 90° and the clamping screws can be inserted axially from the top of the body. In this case it is the conductors of the feed cables that are near to the inner walls of the metal case.
In both cases, the distance between the head of the clamping screw, or the conductor of the feed cable, and the wall of the metal case is sufficient to ensure electrical insulation for connectors used at rated voltages of 250 V, but it is not sufficient to ensure the minimum safety distance required by current international safety standards for connectors used at rated voltages of 400 V.
This drawback is solved at least in part by utility model DE 2001 5602 U, in which a standard type plug-and-socket connector measuring 21×21 mm that can be used for rated voltages of 400 V has been designed. In this plug-and-socket connector the conductors are clamped to the terminals by means of screws. In this case, in order to eliminate the risks due to the small distance between the heads of the screws and the walls of the metal case, an additional element has been introduced in the form of an insulating plastic hood that encloses the live parts of the contacts, shielding them from the metal walls of the case.
The hood can be moved into two locking positions: top and bottom. When the hood is in the top position, the cables can be connected to the screw terminals of the contacts; subsequently it is necessary to push the hood downwards to shield the screw heads from the walls of the case.
This solution is rather complex and costly, because of the provision of an additional element to be inserted into very limited spaces.